Signal processing may involve modification, amplification and/or interpretation of various signals. These signals may include audio, video, speech, data, communication, geophysical, analog, digital and numerous other types of signals. These signals may be processed in many different ways and signal processing generally may be broken into categories (e.g., digital signal processing, analog signal processing, linear signal processing, nonlinear signal processing, continuous-time signal processing and discrete-time signal processing). Typically, certain signal processing categories, such as digital signal processing and analog signal processing, are not mixed together because the techniques for processing the signals via either of these methods may be quite different.
Nevertheless, with the advent of very large scale integration (VLSI) in the manufacture of integrated circuits on semiconductor chips, is possible to include both analog and digital circuits on the same chip, resulting in so-called “mixed-signal” systems. Such systems may typically be divided into clearly digital and clearly analog sub-systems, connected through analog-to-digital and digital-to-analog converters. The converters are used to switch the signal from one signal domain to another. However, it may be desirable to provide for systems where two or more domains, not limited to analog and digital, are mixed together, possibly without converters. In this context, the term “domain” is liberally taken to mean linear, nonlinear, analog, digital, continuous-time, discrete-time, etc. These thoroughly mixed systems may be able to perform the same as a traditionally separated system, but the mixed systems may be able to provide a greater degree of flexibility in processing signals.